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Abstract This study explores the key differences between single-year (SY) and multiyear (MY) El Niño properties and examines their relative importance in causing the diverse evolution of El Niño. Using a CESM1 simulation, observation/reanalysis data, and pacemaker coupled model experiments, the study suggests that the Indian Ocean plays a crucial role in distinguishing between the two types of El Niño evolution through subtropical ENSO dynamics. These dynamics can produce MY El Niño events if the climatological northeasterly trade winds are weakened or even reversed over the subtropical Pacific when El Niño peaks. However, El Niño and the positive Indian Ocean dipole (IOD) it typically induces both strengthen the climatological northeasterly trades, preventing the subtropical Pacific dynamics from producing MY events. MY events can occur if the El Niño fails to induce a positive IOD, which is more likely when the El Niño is weak or of the central Pacific type. Additionally, this study finds that such a weak correlation between El Niño and the IOD occurs during decades when the Atlantic multidecadal oscillation (AMO) is in its positive phase. Statistical analyses and pacemaker coupled model experiments confirm that the positive AMO phase increases the likelihood of these conditions, resulting in a higher frequency of MY El Niño events.
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Multiple Model Systems and Representation of Biological Phenomena
Biologists often study certain biological systems as models of a phenomenon of interest even if they already know that the phenomenon occurs through diverse mechanisms and hence none of those systems can sufficiently represent it by itself. To understand this modeling practice, the present paper provides an account of how multiple model systems can be used to study a phenomenon whose underlying mechanisms are diverse. Even if generalizability of results from a single model system is significantly limited, generalizations concerning particular aspects of mechanisms often hold across certain ranges of biological systems, which enables multiple model systems to jointly represent such a phenomenon. Comparing mechanisms that operate in different biological systems as examples of the same phenomenon also facilitates characterization and investigation of individual mechanisms. I also compare my account with two existing accounts of the use of multiple model systems and argue that my account is distinct from and complementary to them.
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- Award ID(s):
- 1921821
- PAR ID:
- 10309298
- Editor(s):
- Schickore, Jutta
- Date Published:
- Journal Name:
- Integrated HPS Conference Proceedings
- Volume:
- 1
- Issue:
- 1
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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